This invention relates to improvements in and relating to a fluidized-bed type multistage solid-liquid contact apparatus.
The known fluidized-bed type multistage solid-liquid contact apparatus is an integral apparatus which comprises (1) a contact column which consists of a vertical column, a multiplicity of horizontal support plates of water-pervious structure such as perforated plates disposed in the form of multistage shelves within said vertical column, said support plates in the respective shelves excepting the lowermost one being provided each with a tube adapted to permit communication between the upper side and lower side thereof, and a fluidized bed of solid particles such as of activated carbon, ion-exchange resin or the like formed on each of said support plates, (2) a crude liquid tank for storing a crude liquid to be delivered to said contact column for treatment therein, (3) means for delivering said crude liquid from said crude liquid tank to the space below the lowermost support plate in said contact column, (4) a treated liquid tank for storing treated liquid discharged from said contact column, (5) means for delivering said treated liquid from the space above the uppermost support plate of said contact column to said treated liquid tank and (6) means for delivering solid particles to the space above the uppermost support plate in said contact column and means for discharging solid particles from the lowermost support plate in said contact column. The solid particles for fluidized bed are gradually delivered downwardly through the head of the contact column and the crude liquid is continuously introduced into the space below the lowermost support plate in the contact column and allowed to flow up the interior of the contact column. Consequently, solid particles are fluidized on the support plates to form contact layers generally called "fluidized bed", in which layers the solid particles and the crude liquid come into mutual contact. Depending on the particular kind of liquid and solid particles in use, this contact causes a chemical or physical change in the crude liquid. By the time the liquid rises above the uppermost support plate and flows out of the contact column, said chemical or physical change has been completed. Consequently, the liquid thus discharged from the head of the contact column corresponds to what has been referred to as "treated liquid" above. In this conventional apparatus, however, means capable of accurate metering is not incorporated. Therefore, it fails to provide quantitative treatment, though it permits qualitative treatment of the liquid.
Further, in the contact column, the crude liquid flows continuously up the column interior while successively passing the support plates and the solid particles gradually move down the column interior via the downcomers. In this manner, solid particles which have been degraded in activity are gradually discharged through the column bottom and fresh supply of solid particles is introduced through the column head.
It is possible in this case that the downward flow of solid particles via the downcomers will be obstructed by the upward flow of the crude liquid and immobilized solid particles will consequently collect in a heap on one of the multistage shelves even to the extent of blocking the interior of the column completely. As a result, in the support plates below the blocked shelf, downward flow of solid particles alone is permitted to proceed and the supply of solid particles through the column head is stopped. Such phenomenon as this could result in the total absence of solid particles from the column.
The present invention is directed to improving the fluidized-bed type multistage solid-liquid contact apparatus.
A primary object of this invention, therefore, is to provide a fluidized-bed type multistage solid-contact apparatus which permits accurate metering of solid particles to be used therein.
Another object of this invention is to provide a fluidized-bed type multistage solid-liquid contact apparatus which enables the supply of solid particles and the supply of crude liquid to be effected smoothly within the contact column.